Break the biscuits with your hands into smallish pieces. Place into a bowl.
Place the milk and sugar into a small pot and bring to a boil, while stirring from time to time. Boil for about 1 minute. Add the butter and stir until melted.
Take off the heat, add the cocoa and the rum aroma and stir well.
Pour this mixture over the biscuit pieces and stir well until all the biscuit pieces are coated with the cocoa mixture
Cut two pieces of plastic wrap/cling film. Divide the mixture in two and place each batch on one of the cling film pieces. Form a rough sausage and wrap it carefully into the cling film to form a “salami”. Repeat with the second batch.
Put the salami biscuit in the fridge to set overnight. Slice before serving and enjoy it.